How can u tell the difference between a v1 ps2 and a v3?

i have a v1-3 (PAL) ps2 cos it has ten screws but not sure which version...any idea how to check?
also does anybody know if a ps2 v1-3 (PAL)can read dvd+r/rw media (ie backed up dvd games),
anyone got this to work?

it will defintley not read +r media espeacially +rw even newer ps2's have trouble reading rw disks and anyway theres not exactly any advantage to have a game on a rw disk apart from being able to erase it which defeats the object of making the backup in the first place